X-Git-Url: https://git.camperquake.de/gitweb.cgi?a=blobdiff_plain;f=module%2Fzfs%2Fdsl_dir.c;fp=module%2Fzfs%2Fdsl_dir.c;h=97b38d209bff315d79c88237f81d913440e5a27b;hb=65947351e71bec2ec5673bf0c3ad02f2c2b96b6c;hp=d615832c56c20c750ed90e1915dc02806d4a3fdb;hpb=d13524579162b35189804c357a63993be758b84c;p=zfs.git

diff --git a/module/zfs/dsl_dir.c b/module/zfs/dsl_dir.c
index d615832..97b38d2 100644
--- a/module/zfs/dsl_dir.c
+++ b/module/zfs/dsl_dir.c
@@ -460,12 +460,14 @@ dsl_dir_destroy_check(void *arg1, void *arg2, dmu_tx_t *tx)
 	/*
 	 * There should be exactly two holds, both from
 	 * dsl_dataset_destroy: one on the dd directory, and one on its
-	 * head ds.  Otherwise, someone is trying to lookup something
-	 * inside this dir while we want to destroy it.  The
-	 * config_rwlock ensures that nobody else opens it after we
-	 * check.
+	 * head ds.  If there are more holds, then a concurrent thread is
+	 * performing a lookup inside this dir while we're trying to destroy
+	 * it.  To minimize this possibility, we perform this check only
+	 * in syncing context and fail the operation if we encounter
+	 * additional holds.  The dp_config_rwlock ensures that nobody else
+	 * opens it after we check.
 	 */
-	if (dmu_buf_refcount(dd->dd_dbuf) > 2)
+	if (dmu_tx_is_syncing(tx) && dmu_buf_refcount(dd->dd_dbuf) > 2)
 		return (EBUSY);
 
 	err = zap_count(mos, dd->dd_phys->dd_child_dir_zapobj, &count);